SIGNAL INTERRUPT DETECTION CIRCUIT, COMMUNICATION CLOCK REPRODUCING DEVICE AND DATA REPRODUCING DEVICE INCORPORATING THE CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a signal interrupt detection circuit with an improved signal interrupt and resetting speed, a communication clock reproducing device and a data reproducing device incorporating this circuit. SOLUTION: The signal interrupt detection circuit to be incorporated into a communication clock reproducing device provided with a two-multiplication circuit 1, a clock extraction filter 2, a limiting amplifier circuit 3 and a phase adjusting circuit 4 or into a data reproducing device provided with a discrimination circuit 5, in addition to the clock extraction filter and the circuits mentioned above uses loss output obtained by comparing an envelope amplitude signal obtained by envelope-detecting a basic clock component which is extracted by filtering a signal from the two-multiplication circuit with a quasi- narrow band pass filter 11 having a frequency selection degree lower than the frequency selection degree (Q value) of the clock extraction filter by an envelope detection circuit 12 with a fixed threshold by a comparator circuit 13.